A. Field of the Invention
The present invention relates generally to memory management systems and, more particularly, to systems and methods for allocating memory using a memory address pool.
B. Description of Related Art
Memory management systems conventionally use memory address pools, commonly called freelists, for managing memory. In many memory management systems, memory is divided into blocks with the addresses of these blocks stored in a secondary memory array to form a free memory address pool. This free address pool can be managed as a first-in-first-out (FIFO) queue. Addresses are removed from the free address pool when a block is allocated in memory for writing data. Addresses are then returned to the free address pool when a block is de-allocated from memory after, for example, the data is read out of memory.
One problem that occurs with the use of a free address pool is when a memory “leak” occurs that causes a memory block to not be de-allocated. When memory leaks occur, there is the possibility that the free address pool will become depleted. This can create serious problems, since the system will be unable to allocate any further memory until blocks are de-allocated. Conventionally, memory management systems have been designed to handle memory leaks by “aging” memory blocks and returning the block addresses to the free address pool after a certain period of time. This, solution, however, also has its own attendant problems. When memory blocks are “aged,” requests may subsequently be made for a memory block that has already been de-allocated because of its age. This problem is called “aliasing.” Aliasing has two detrimental effects. First, the data integrity cannot be guaranteed, since data that is read might not be valid data. Second, the free address pool may become “polluted” because a memory block might have multiple addresses in the address pool.
Therefore, there exists a need for memory management systems and methods that can implement free address pools for reading and writing data to memory, without incurring aliasing and address pool pollution.